NSFNET

Introduction

NSFNET was a computer network funded by the National
Science Foundation (NSF), which is an agency of the government of the United
States of America. NSFNET stands for the 'National Science Foundation Network',
and from 1987-1992, NSFNET was viewed as the backbone network/infrastructure
of the Internet. The original NSFNET backbone consisted of six supercomputer
locations, which were located at U.S. universities and research institutions.
NSFNET used the TCP/IP protocol suite to connect and transport data across
its network; the Internet is a term coined by the computer scientists who
designed TCP/IP and described the ability of TCP/IP to interconnect computer
network into one large super-network. In 1987, Ed Krol wrote the Hitchhiker's
Guide, which was the first popular guide for the Internet, and gave a
detailed description of NSFNET; this book is now republished as RFC 1118.

NSFNET evolves from ARPANET and CSNET

ARPANET was the first computer network in the United States to connect research
and education institutions. ARPANET pioneered packet switching, and the TCP/IP
protocol suite was invented by Vint Cerf and Bob Kahn, in the 1970s, as an
improvement to ARPANET host-to-host protocol program. Due to the Mansfield
Amendment of 1973, the Department of Defense (ARPA was a US defense agency)
was directed to no longer fund the development of science projects. ARPANET
was split into a military and a research network, and the research network
of ARPANET was planned to be slowly phased out from 1975 onwards.

(Pictured: NSFNET Logo and Map of NSFNET Supercomputer Centre's)

Due to a lack of funding to expand and develop ARPANET, the National Science
Foundation (NSF) funded the creation of CSNET (Computer
Science Network). In 1979, Lawrence Landweber, Professor Emeritus of Computer
Science at the University of Wisconsin, had proposed the creation of CSNET,
with support from Dave Crocker, Vint Cerf and DARPA, to connect U.S. universities,
industries and government computer research groups. His proposal received
$5 million in funding in January 1980, and the team who built CSNET included:
L. Landweber, B. Kern, P. Denning, and T. Hearn. One of the reasons CSNET
was created was to connect U.S. research and education institutions who could
not connect to ARPANET.

CSNET initially connected the following U.S. institutions (amongst others):
University of Minnesota, University of Wisconsin, University of Oklahoma,
University of California-Berkeley, and Yale University. From 1981-1984, CSNET
was funded by the National Science Foundation, and by 1984 the network had
been connected to over 150 universities. Due to the success of CSNET, the
National Science Foundation planned the creation of a new expanded network
in 1984: NSFNET. When NSFNET was launched 1986, it soon eclipsed ARPANET and
CSNET, which were both slowly decommissioned from 1985-1991.

NSFNET is planned

The National Science Foundation (NSF) funded a range of computer science
projects: chief amongst them was the creation of a supercomputing program
in the early 1980s. Science projects had increasingly become reliant on computers,
and relied upon powerful computing power. Part of the NSF's supercomputing
program was to connect the supercomputers together to form a computer network.
This network would become NSFNET, and it was envisaged that data could travel
up to twenty-five times faster on NSFNET than it could on CSNET: due to the
power of the supercomputers. By 1984, the NSF had funded the construction
of supercomputers at the following locations:

Princeton University (John von Neumann Center)

University of California, San Diego (Supercomputer Center)

University of Illinois (National Center for Supercomputing
Applications)

Cornell University (Cornell Theory Center)

University of Pittsburgh (Pittsburgh Supercomputing Center
(PSC))

National Center for Atmospheric Research (NCAR)

In 1985, the NSF hired Dennis Jennings to manage the creation of NSFNET,
Jennings was an Irish physicist and computer networking pioneer who was an
active participant in the creation of the TERENA European research network.
Jennings decided that NSFNET would: function as an all-purpose research network;
it would act as a backbone network that would facilitate the connection of
regional networks to it; and it would use the TCP/IP protocol suite that had
been implemented on CSNET, MILNET and ARPANET. The infrastructure plan, outlined
by Jennings, for NSFNET was as follows: -Backbone (supercomputer centers);
-Tier Two: Regional Networks; -Tier Three: Campus Networks.

(Pictured: Dennis Jennings, program director for NSFNET)

The development of TCP/IP had been funded by DARPA, and it became a Department
of Defense standard in the early 1980s. When NSF picked TCP/IP for its network,
it had elected to support the DARPA Internet organisational infrastructure,
such as the IAB, that managed the development of TCP/IP and its namespace
resources. During the 1980s, there was a competition between the IP and OSI
networking models, referred to as the protocol war, and it was feasible
that Jennings could have used OSI instead of IP for NSFNET. Jennings decision
was crucial for the development of IP networks, which would eventually interconnect
to become the modern Internet in the early 1990's.

NSFNET is operational

By the end of 1986, NSFNET was operational, and the team that built NSFNET
included: members of NCSA (included Ed Krol and C. Kline); members of CUTC
(included A. Brown and S. Brim); members of the University of Delaware (included
D. Farber and D. Mills); and H.W. Braun of Merit. NSFNET was built upon a
backbone of six supercomputer locations, operating at a data speed of 56 K-bit/sec,
with each supercomputer connected to a newly designed 'fuzzball'
router - the fuzzball tested new routing protocols like NTP.

The first problem that arose with the NSFNET backbone was its data speed:
as more regional networks were connected, traffic congestion became an issue,
and it became apparent that the NSFNET backbone infrastructure needed to be
upgraded to support a faster data speed. In 1987, program director Steve Wolff
solicited the private sector to upgrade the NSFNET infrastructure. In 1987,
NSFNET signed a $39 million five-year cooperative agreement with Merit, IBM,
and MCI to upgrade the NSFNET backbone. In 1988, the NSFNET backbone was upgraded
to a 1.5 Mbit/s T1 network that featured thirteen nodes, and by 1991, it had
been upgraded to a 45 Mbit/s T3 network that featured sixteen nodes. IBM focused
on upgrading the packet switching hardware and software of NSFNET, and MCI
upgraded the transmission circuits.

From 1987-1991, the NSFNET backbone was connected to a variety
of regional and federal computer networks. To name but a few:

BARRNet (Bay Area Regional Research Network)

ESnet (Energy Sciences Network)

MichNet (Michigan Network)

MIDnet (Midwest Network)

MILNET (Military Network)

NSN (NASA Science Network)

NorthWestNet (North West Network)

NYSERNet (New York State Education and Research Network)

SESQUINET (Sesquicentennial Network)

SURAnet (South Eastern Universities Research Association Network)

Westnet (West State Network)

Most of the regional networks listed above were connected to smaller (campus)
networks, which numbered in the thousands. NSFNET was interconnected to other
U.S. federal networks when the Federal
Internet Exchange (FIX) was established in 1989. Therefore, for the first
time, a 'network of networks' was formed, that would closely resemble the
modern Internet. The NSFNET backbone was at the 'heart' of this configuration,
and became known as the Internet's backbone. By 1992, over 4,000 networks
in the United States, and over 2000 international networks, were connected
to the NSFNET backbone.

NSFNET and commercialisation

NSFNET was designed to foster communication between educational and research
institutions in the United States of America. Therefore, the NSF, generally
speaking, did not allow commercial use of its backbone network. By 1991, commercial
networks (Internet Service Providers) were being founded to provide public/commercial
access to IP networks. NSFNET created an 'Acceptable Use Policy' to allow
these networks to connect to the NSFNET backbone. The problem was that the
'Acceptable Use Policy' of NSFNET did not allow unrestricted commercial use.
In 1991, three commercial computer networks decided to create the Commercial
Internet Exchange (CIX) : CIX would allow commercial traffic to be exchanged
between commercial networks, which included:

CERFnet (California Education and Research Federation Network)

PSInet (Northern Virginia Network)

UUnet (UUNET Communications Services)

At the same time, Merit, IBM, and MCI created a new commercial Internet Service
Provider, named ANS CO+RE, that used the network infrastructure designed for
NSFNET. Therefore, a situation arose where the network hardware of NSFNET
was being used for two purposes: the NSF backbone service and the commercial
traffic of ANS CO+RE. Another problem arose when ANS CO+RE refused to interconnect
their network with the Commercial Internet Exchange (CIX): which created a
perceived monopoly of the network hardware of the NSFNET backbone. While a
compromise was eventually reached between ANS CO+RE and CIX, the controversy
created by the situation would lead to a reorganisation of the Internet's
backbone.

Instead of a centralised Internet backbone, that was federally funded by
the U.S. government, it was decided that the backbone of the Internet would
consist of commercial networks - typically large telecom companies - who would
charge people to access their network. The transition from the NSFNET backbone
to a privatised commercial backbone was a drawn out process, involving Network
Access Points (NAP), that exchanged data between these commercial backbone
networks. NAPs were the forerunner of Internet Exchange Points; such as The
London Internet Exchange (LINX). The NSFNET backbone was officially decommissioned
on the 30th of April 1995. NSFNET was instrumental in the development of the
modern Internet.